Copper sulfate, when it is dissolved in water, has a blue color. When steel wool is mixed with a copper sulfate solution, the st
eel wool disappears, a brownish solid forms, and the color of the solution changes from blue to green. Choose one answer that gives the best evidence that a chemical reaction took place.
A. The color change from blue to green happens in nature.
B. The disappearance of the steel wool shows that a new substance has formed.
C. The solid precipitate is a waste product in the reaction.
D. Energy is lost in this reaction like all other reactions.
Which answer did you choose? Explain your reasoning.
A. The color change from blue to green happens in nature.
Explanation:
The color change is an indicator of a chemical reaction that has occurred. Although color changes are not necessarily good diagnostic tool to measure if a chemical reaction has occurred or not.
In this reaction, color changes is quite an effective tool
Chemical changes usually involves the formation of a new product from the chemical reaction.
Also, the steps are not easily reversible.
For this reaction, color change is the most appropriate signal for a chemical change.
